/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.runtime.minicluster;

import org.apache.flink.runtime.execution.Environment;
import org.apache.flink.runtime.jobgraph.tasks.AbstractInvokable;

import java.util.Collections;
import java.util.Set;
import java.util.concurrent.ThreadLocalRandom;

/**
 * {@link org.apache.flink.runtime.testtasks.BlockingNoOpInvokable} that sometimes fails.
 */
public class SometimesExceptionSender extends AbstractInvokable {

	private static Set<Integer> failingSenders;

	public SometimesExceptionSender(Environment environment) {
		super(environment);
	}

	static void configFailingSenders(int numTasks) {
		failingSenders = Collections.singleton(ThreadLocalRandom.current().nextInt(numTasks));
	}

	@Override
	public void invoke() throws Exception {
		if (failingSenders.contains(this.getIndexInSubtaskGroup())) {
			throw new Exception("Test exception");
		} else {
			final Object o = new Object();
			//noinspection SynchronizationOnLocalVariableOrMethodParameter
			synchronized (o) {
				//noinspection InfiniteLoopStatement
				while (true) {
					o.wait();
				}
			}
		}
	}
}
